Method to distinguish ferroelectric from nonferroelectric origin in case of resistive switching in ferroelectric capacitors

Abstract

We present investigations on the resistive switching effect in SrRuO3∕PbZr0.2Ti0.8O3∕Pt ferroelectric capacitors. Using a conductive atomic force microscope, the out-of-plane piezoelectric response and the capacitive and resistive current were simultaneously measured as a function of applied bias voltage. We observed two independent switching phenomena, one attributed to the ferroelectric switching process and the other to resistive switching.We show that I-V curves alone are not sufficient in ferroelectric materials to clarify the underlying switching mechanism and must be used with sufficient caution.

Giant electrode effect on tunnelling electroresistance in ferroelectric tunnel junctions

“…Furthermore, the TER effect associated with ferroelectric switching is inferred from the occurrence of resistance switching at voltages corresponding to the coercive fields of the ferroelectric tunnel barrier. However, as pointed out earlier, this necessary condition is not sufficient to distinguish the ferroelectric-driven TER (FE-TER) from resistance-switching phenomena resulting from-so to speak-'redox' reactions 35 . Indeed, given that the very high coercive fields of ultrathin ferroelectric films fall into the electric-field range where the occurrence of a soft breakdown of the film cannot be excluded, there remain concerns that stochastic redox-based resistance switching might be misinterpreted as the FE-TER [36][37][38][39][40][41] .…”

“…Although the occurrence of the resistive switching in our FTJs at the coercive voltages of the BTO barrier indicates its ferroelectric origin, BTO is also known as a redox-based resistance-switching material 35 . Therefore, it is critically important to investigate the redox-based resistive switching behaviour of our FTJs to clearly distinguish this mechanism from the FE-TER effect.…”

Tunnel electroresistance in junctions with ultrathin ferroelectric Pb(Zr0.2Ti0.8)O3 barriers

“…[3][4][5][6][7][8][9][10][11][12] However, there are mechanisms other than ferroelectric polarization switching, which might contribute to or generate a resistive switching effect, such as, for instance, surface electrochemical reactions. 4,13 Especially, experiments performed in ambient conditions by using a conductive atomic force microscope (AFM) tip in contact with a ferroelectric surface are prone to such effects. 14 Up to now, most of the measurements performed on ferroelectric barriers with thicknesses small enough to allow direct quantum-mechanical tunneling have been performed by such a method.…”

Scaling of electroresistance effect in fully integrated ferroelectric tunnel junctions

“…The nearly constant R ON Â A product with a mean of $0.05 X cm 2 for different areas FTJ matches with the reported value 34 verifying the ferroelectric switching at nanoscale. 33 The average %TER is 1.5 Â 10 4 % among the measured devices with a maximum observed TER is 1.6 Â 10 5 % for a 400 Â 400 nm 2 FTJ. The switching cycle measurement shows an endurance of $20, after that OFF/ON resistance ratio becomes $1.…”

“…The current compliance was set at 20 nA to prevent any local joule heating or electroforming in FTJs. 33 I-V curve during read operation obtained in a 200 Â 200 nm 2 FTJ is shown in Fig. 4(a).…”